scholarly journals Screening Cotoneaster for Resistance to Fire Blight by Artificial Inoculation

HortScience ◽  
2014 ◽  
Vol 49 (12) ◽  
pp. 1480-1485 ◽  
Author(s):  
Joseph J. Rothleutner ◽  
Ryan N. Contreras ◽  
Virginia O. Stockwell ◽  
James S. Owen
Keyword(s):  
Disease Resistance ◽  
Fire Blight ◽  
Bacterial Pathogen ◽  
Artificial Inoculation ◽  
Lesion Length ◽  
Sources Of Resistance ◽  
Landscape Plants ◽  
Whole Plant ◽  
Wide Range ◽  
Disease Pressure

Cotoneaster Medik. is a genus of ornamental landscape plants commonly affected by fire blight. Fire blight is a disease caused by the bacterial pathogen, Erwinia amylovora (Burrill) Winslow et al., that attacks a wide range of taxa in the apple subfamily (Maloideae; Rosaceae). To assess susceptibility of species and identify potential sources of resistance, we inoculated 52 taxa of Cotoneaster with E. amylovora. Disease severity was scored by percent shoot necrosis (lesion length/total shoot length). Disease screenings were conducted over 2 years and varying levels of susceptibility were observed. Some taxa were highly susceptible to fire blight and the disease resulted in whole plant mortality (C. rhytidophyllus Rehder & E.H. Wilson, C. rugosus E. Pritzel ex Diels, and C. wardii W.W. Smith). Other taxa repeatedly exhibited moderate to high levels of disease resistance [C. arbusculus G. Klotz, C. chungtinensis (T.T. Yu) J. Fryer & B. Hylmö, C. delsianus E. Pritzel var. delsianus, C. sikangensis Flinck & B. Hylmö, C. simonsii Baker, and C. splendens Flinck & Hylmö]. Ongoing studies are being conducted to determine if taxa with high levels of resistance under artificial inoculation will exhibit high levels of resistance in the field under natural disease pressure. Identifying sources of disease resistance will be useful for breeding programs to increase tolerance of these landscape plants with desirable horticultural characteristics to fire blight.

scholarly journals Variation in Susceptibility of Tanoak to the NA1 and EU1 Lineages of Phytophthora ramorum, the Cause of Sudden Oak Death

Plant Disease ◽  
2019 ◽  
Vol 103 (12) ◽  
pp. 3154-3160 ◽  
Author(s):  
Kelsey L. Søndreli ◽  
Alan Kanaskie ◽  
Susanna Keriö ◽  
Jared M. LeBoldus
Keyword(s):  
Disease Resistance ◽  
Forest Ecosystems ◽  
Phytophthora Ramorum ◽  
Sudden Oak Death ◽  
Artificial Inoculation ◽  
Lesion Length ◽  
Significant Difference ◽  
Notholithocarpus Densiflorus ◽  
The Impact ◽  
Inoculation Assay

Phytophthora ramorum, the cause of sudden oak death (SOD), kills tanoak (Notholithocarpus densiflorus) trees in southwestern Oregon and California. Two lineages of P. ramorum are now found in wildland forests of Oregon (NA1 and EU1). In addition to the management of SOD in forest ecosystems, disease resistance could be used as a way to mitigate the impact of P. ramorum. The objectives of this study were to (i) characterize the variability in resistance of N. densiflorus among families using lesion length; (ii) determine whether lineage, isolate, family, or their interactions significantly affect variation in lesion length; and (iii) determine whether there are differences among isolates and among families in terms of lesion length. The parameters isolate nested within lineage (isolate[lineage]) and family × isolate(lineage) interaction explained the majority of the variation in lesion length. There was no significant difference between the NA1 and EU1 lineages in terms of mean lesion length; however, there were differences among the six isolates. Lesions on seedlings collected from surviving trees at infested sites were smaller, on average, than lesions of seedlings collected from trees at noninfested sites (P = 0.0064). The results indicate that there is potential to establish a breeding program for tanoak resistance to SOD and that several isolates of P. ramorum should be used in an artificial inoculation assay.

scholarly journals Resistance to Foliar Diseases in a Mini-Core Collection of Sorghum Germplasm

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1629-1633 ◽  
Author(s):  
Rajan Sharma ◽  
H. D. Upadhyaya ◽  
S. V. Manjunatha ◽  
V. P. Rao ◽  
R. P. Thakur
Keyword(s):  
Disease Resistance ◽  
Core Collection ◽  
Natural Infection ◽  
Morphological Characteristics ◽  
Leaf Blight ◽  
Flowering Plant ◽  
Artificial Inoculation ◽  
Foliar Diseases ◽  
Mini Core Collection ◽  
Wide Range

Anthracnose, leaf blight, and rust are important biotic constraints to grain and forage sorghum production worldwide and are best managed through host plant resistance. A sorghum mini-core collection, consisting of 242 germplasm accessions developed from a core collection of 2,246 landrace accessions originating from 58 countries, was evaluated to identify sources of resistance to foliar diseases. The mini-core accessions were evaluated in anthracnose- and leaf-blight-screening nurseries under artificial inoculation in the rainy and late rainy seasons, respectively, during 2009 and 2010. For rust resistance, screening was done under artificial inoculation in the greenhouse as well as in the field under natural infection. In all, 13 accessions were found resistant (score ≤3.0 on a 1-to-9 scale) to anthracnose and 27 to leaf blight in both 2009 and 2010. Six accessions exhibited resistance to rust in both the greenhouse and the field. In the resistant accessions, a wide range of diversity was observed for agronomic traits such as days to 50% flowering, plant height, and grain yield/plant, and morphological characteristics such as grain or glume color, glume coverage, endosperm texture, and panicle type (ear head compactness). Three mini-core accessions (IS 473, IS 23684, and IS 23521) exhibited resistance to all three diseases. These accessions with multiple disease resistance will be useful in sorghum disease resistance breeding programs.

scholarly journals Resistance of Raspberry Cultivars to Fire Blight

HortScience ◽  
2004 ◽  
Vol 39 (6) ◽  
pp. 1189-1192 ◽  
Author(s):  
P.G. Braun ◽  
P.D. Hildebrand ◽  
A.R. Jamieson
Keyword(s):  
Disease Severity ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Rubus Idaeus ◽  
The Other ◽  
Lesion Length ◽  
Disease Development ◽  
Red Raspberry ◽  
Progress Curve ◽  
Wide Range

Twenty-five cultivars of red raspberry (Rubus idaeus L.) and one purple raspberry (R. occidentalis L. × R. idaeus L.) were evaluated for their resistance to fire blight caused by Erwinia amylovora (Burr.) Winslow et al. Actively growing raspberry cane tips were wound inoculated with three isolates of the pathogen and disease development was assessed over 17 days. Three methods of evaluating resistance were used: area under the disease progress curve (AUDPC), a weighted AUDPC called the area under the disease severity curve (AUDSC), and lesion length. A wide range of resistance levels was observed, but no cultivars were symptomless. Primocane-fruiting cultivars tended to be more resistant than floricane-fruiting ones. Of the three E. amylovora isolates used in this study, one was significantly more virulent than the other two, but no cultivar × isolate interaction was detected.

scholarly journals Citizen views on genome editing: effects of species and purpose

2021 ◽  
Author(s):  
Gesa Busch ◽  
Erin Ryan ◽  
Marina A. G. von Keyserlingk ◽  
Daniel M. Weary
Keyword(s):  
Disease Resistance ◽  
Product Quality ◽  
Genome Editing ◽  
Total Sample ◽  
Moral Foundations ◽  
Perceived Risks ◽  
Public Response ◽  
The Public ◽  
Wide Range ◽  
The Us

AbstractPublic opinion can affect the adoption of genome editing technologies. In food production, genome editing can be applied to a wide range of applications, in different species and with different purposes. This study analyzed how the public responds to five different applications of genome editing, varying the species involved and the proposed purpose of the modification. Three of the applications described the introduction of disease resistance within different species (human, plant, animal), and two targeted product quality and quantity in cattle. Online surveys in Canada, the US, Austria, Germany and Italy were carried out with a total sample size of 3698 participants. Using a between-subject design, participants were confronted with one of the five applications and asked to decide whether they considered it right or wrong. Perceived risks, benefits, and the perception of the technology as tampering with nature were surveyed and were complemented with socio-demographics and a measure of the participants’ moral foundations. In all countries, participants evaluated the application of disease resistance in humans as most right to do, followed by disease resistance in plants, and then in animals, and considered changes in product quality and quantity in cattle as least right to do. However, US and Italian participants were generally more positive toward all scenarios, and German and Austrian participants more negative. Cluster analyses identified four groups of participants: ‘strong supporters’ who saw only benefits and little risks, ‘slight supporters’ who perceived risks and valued benefits, ‘neutrals’ who showed no pronounced opinion, and ‘opponents’ who perceived higher risks and lower benefits. This research contributes to understanding public response to applications of genome editing, revealing differences that can help guide decisions related to adoption of these technologies.

scholarly journals Integration of early disease-resistance phenotyping, histological characterization, and transcriptome sequencing reveals insights into downy mildew resistance in impatiens

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ze Peng ◽  
Yanhong He ◽  
Saroj Parajuli ◽  
Qian You ◽  
Weining Wang ◽  
...  
Keyword(s):  
Disease Resistance ◽  
Downy Mildew ◽  
Transcriptome Sequencing ◽  
Early Stage ◽  
Economic Losses ◽  
Potential Candidate ◽  
Early Disease ◽  
True Leaf ◽  
Cotyledon Stage ◽  
Wide Range

AbstractDowny mildew (DM), caused by obligate parasitic oomycetes, is a destructive disease for a wide range of crops worldwide. Recent outbreaks of impatiens downy mildew (IDM) in many countries have caused huge economic losses. A system to reveal plant–pathogen interactions in the early stage of infection and quickly assess resistance/susceptibility of plants to DM is desired. In this study, we established an early and rapid system to achieve these goals using impatiens as a model. Thirty-two cultivars of Impatiens walleriana and I. hawkeri were evaluated for their responses to IDM at cotyledon, first/second pair of true leaf, and mature plant stages. All I. walleriana cultivars were highly susceptible to IDM. While all I. hawkeri cultivars were resistant to IDM starting at the first true leaf stage, many (14/16) were susceptible to IDM at the cotyledon stage. Two cultivars showed resistance even at the cotyledon stage. Histological characterization showed that the resistance mechanism of the I. hawkeri cultivars resembles that in grapevine and type II resistance in sunflower. By integrating full-length transcriptome sequencing (Iso-Seq) and RNA-Seq, we constructed the first reference transcriptome for Impatiens comprised of 48,758 sequences with an N50 length of 2060 bp. Comparative transcriptome and qRT-PCR analyses revealed strong candidate genes for IDM resistance, including three resistance genes orthologous to the sunflower gene RGC203, a potential candidate associated with DM resistance. Our approach of integrating early disease-resistance phenotyping, histological characterization, and transcriptome analysis lay a solid foundation to improve DM resistance in impatiens and may provide a model for other crops.

scholarly journals In-field screening for host plant resistance to Delia radicum and Brevicoryne brassicae within selected rapeseed cultivars and new interspecific hybrids

2020 ◽  
Vol 15 (1) ◽  
pp. 711-720
Author(s):  
Janetta Niemann ◽  
Justyna Szwarc ◽  
Jan Bocianowski ◽  
Dorota Weigt ◽  
Marek Mrówczyński
Keyword(s):  
Life Sciences ◽  
Field Trials ◽  
Brevicoryne Brassicae ◽  
Delia Radicum ◽  
Sources Of Resistance ◽  
Cabbage Aphid ◽  
Hybrid Combination ◽  
Resistance To Insects ◽  
Wide Range ◽  
High Level

AbstractRapeseed (Brassica napus) can be attacked by a wide range of pests, for example, cabbage root fly (Delia radicum) and cabbage aphid (Brevicoryne brassicae). One of the best methods of pest management is breeding for insect resistance in rapeseed. Wild genotypes of Brassicaceae and rapeseed cultivars can be used as a source of resistance. In 2017, 2018, and 2019, field trials were performed to assess the level of resistance to D. radicum and B. brassicae within 53 registered rapeseed cultivars and 31 interspecific hybrid combinations originating from the resources of the Department of Genetics and Plant Breeding of Poznań University of Life Sciences (PULS). The level of resistance varied among genotypes and years. Only one hybrid combination and two B. napus cultivars maintained high level of resistance in all tested years, i.e., B. napus cv. Jet Neuf × B. carinata – PI 649096, Galileus, and Markolo. The results of this research indicate that resistance to insects is present in Brassicaceae family and can be transferred to rapeseed cultivars. The importance of continuous improvement of rapeseed pest resistance and the search for new sources of resistance is discussed; furthermore, plans for future investigations are presented.

Combinatorial Synthesis of Novel 3/5(3,5)-(Di)nitro/chloropaeonol Carbonyl Hydrazone Derivatives as Nematicidal Agents

2021 ◽  
Vol 24 ◽  
Author(s):  
Genqiang Chen ◽  
Lina Zhu ◽  
Yanfei Xia ◽  
Jinming Yang ◽  
Song Zhang ◽  
...  
Keyword(s):  
High Efficiency ◽  
Biological Activities ◽  
Science Research ◽  
Nematicidal Activity ◽  
Effective Control ◽  
Root Bark ◽  
Naturally Occurring ◽  
Whole Plant ◽  
Wide Range

Background: Developing the high-efficiency and low-risk small-molecule green-nematocide is the key of effective control of the nematodes. Paeonol, is a naturally occurring phenolic compound, isolated from the root bark of Paeonia suffruticosa and the whole plant of Cynanchum paniculatum. Due to its crucial phenolic ketone skeleton, modern biological science research has indicated that paeonol has a wide range of biological activities. The structural modification of paeonol into paeonol carbonyl hydrazone derivatives is a potential approach for the development of novel nematodes, which showed more toxicity than paeonol. However, there are no reports on the nematicidal activity of paeonol carbonyl hydrazone derivatives to control Heterodera glycines. Results: We always endeavor to discover and develop biorational natural products-based pesticidal agents, 4 significant intermediates and 21 novel 3/5(3,5)-(di)nitro/chloropaeonol carbonyl hydrazone derivatives were prepared, and their structures well characterized by 1H NMR, HRMS, MS, and mp. Due to the steric hindrance, the substituents on the C=N double bond of all hydrazine compounds adopted E configuration. Results of nematicidal activity revealed that, among all compounds, especially 5-nitropaeonol (5) and 3,5-dinitropaeonol (7) displayed the most potent nematicidal activity H. glycines in vivo with LC50 values of 0.0323 and 0.0367 mg/mL, respectively. Conclusion: It suggested that for the 3/5(3,5)-(di)nitro/chloropaeonol carbonyl hydrazone derivatives, a nitro group introduced at C5 position of 1 was necessary for obtaining the potent compound as nematicidal agents. These preliminary results will pave the way for further modification of paeonol in the development of potential new nematicides.

scholarly journals Identification and Characterization of Diaporthe ambigua, D. australafricana, D. novem, and D. rudis Causing a Postharvest Fruit Rot in Kiwifruit

Plant Disease ◽  
2017 ◽  
Vol 101 (8) ◽  
pp. 1402-1410 ◽  
Author(s):  
Gonzalo A. Díaz ◽  
Bernardo A. Latorre ◽  
Mauricio Lolas ◽  
Enrique Ferrada ◽  
Paulina Naranjo ◽  
...  
Keyword(s):  
San Francisco ◽  
Plant Pathogens ◽  
Elongation Factor ◽  
Its Region ◽  
Fruit Rot ◽  
Lesion Length ◽  
Translation Elongation ◽  
Wide Range ◽  
Postharvest Rot ◽  
Diaporthe Ambigua

Diaporthe spp. are important plant pathogens causing wood cankers, blight, dieback, and fruit rot in a wide range of hosts. During surveys conducted during the 2013 and 2014 seasons, a postharvest rot in Hayward kiwifruit (Actinidia deliciosa) was observed in Chile. In order to identify the species of Diaporthe associated with this fruit rot, symptomatic fruit were collected from seven kiwifruit packinghouses located between San Francisco de Mostazal and Curicó (central Chile). Twenty-four isolates of Diaporthe spp. were identified from infected fruit based on morphological and cultural characters and analyses of nucleotides sequences of three loci, including the internal transcribed spacer (ITS) region (ITS1-5.8S-ITS2), a partial sequences of the β-tubulin, and translation elongation factor 1-α genes. The Diaporthe spp. identified were Diaporthe ambigua, D. australafricana, D. novem, and D. rudis. Multilocus phylogenetic analysis revealed that Chilean isolates were grouped in separate clades with their correspondent ex-types species. All species of Diaporthe were pathogenic on wounded kiwifruit after 30 days at 0°C under normal and controlled-atmosphere (2% O2 and 5% CO2) storage and they were sensitive to benomyl, pyraclostrobin, and tebuconazole fungicides. D. ambigua isolates were the most virulent based on the lesion length measured in inoculated Hayward and Jintao kiwifruit. These findings confirm D. ambigua, D. australafricana, D. novem, and D. rudis as the causal agents of kiwifruit rot during cold storage in Chile. The specie D. actinidiae, a common of Diaporthe sp. found associated with kiwifruit rot, was not identified in the present study.

RESISTANCE TO DIEBACK DISEASE CAUSED BY FUSARIUM AND LASIODIPLODIA SPECIES IN CACAO (THEOBROMA CACAO L.) GENOTYPES

2011 ◽  
Vol 48 (1) ◽  
pp. 85-98 ◽  
Author(s):  
RICHARD ADU-ACHEAMPONG ◽  
SIMON ARCHER ◽  
SIMON LEATHER
Keyword(s):  
Biological Sciences ◽  
Theobroma Cacao ◽  
Genotypic Differences ◽  
Sources Of Resistance ◽  
Cross Sectional ◽  
Assessment Scores ◽  
Sahlbergella Singularis ◽  
Wide Range ◽  
Dieback Disease ◽  
Moderately Resistant

SUMMARYFusarium and Lasiodiplodia species invade feeding lesions caused by mirid bugs (Distantiella theobroma [Dist.] and Sahlbergella singularis Hagl.) and inflict serious damage and yield loss to susceptible cacao (Theobroma cacao L.) varieties in West Africa. As it is the fungal invasion rather than the physical feeding injury by mirids that cause dieback and tree death in cacao, a dieback resistance strategy in cacao crop must take into account resistance to these causal agents. Twenty-nine and 15 cacao genotypes were screened in the laboratory and the greenhouse, respectively, for resistance to isolates of Fusarium decemcellulare and Lasiodiplodia theobromae at Imperial College London's Biological Sciences Campus, UK. Resistance was assessed as the size of necrotic lesions, distance of fungal colonisation in the stem and the proportion of seedlings with dieback symptoms. Genotypic differences were found in both laboratory and greenhouse tests among various cacao genotypes, and the clones showed a wide range of disease reactions from highly resistant to very susceptible. The pathogenicity of F. decemcellulare and L. theobromae were similar in this study, which suggests that a breeding programme for controlling one of the pathogens can have benefit against the other. Direct significant correlations (r = 0.7) were obtained between visual dieback assessment scores and the percentage cross-sectional area of stem necrosis. Moreover, the response of inoculated stem segments corresponded to the reaction of intact plants despite the variation in the used methodology. Three cacao genotypes (CATIE 1000, T85/799 and MXC 67) were resistant or moderately resistant to F. decemcellulare and L. theobromae. These genotypes could be useful sources of resistance to both pathogens and other wilt causing pathogens in cacao.

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